1. Field of the Invention
The present invention generally relates to a side wall barrier and a fabricating method thereof More particularly, the present invention relates to a side wall barrier of an environmentally sensitive electronic device and a fabricating method of an environmentally sensitive electronic device.
2. Description of Related Art
Compared with normal rigid substrates, flexible substrates have a wider range of applications due to their advantages of flexibility, ease of carriage, safety, and applications in consumer products. However, their drawbacks include a large coefficient of thermal expansion and poor resistance to heat, moisture, oxygen, and chemicals. Since typical flexible substrates cannot entirely avoid the transmission of water vapor and oxygen, devices on these substrates experience accelerated aging. Consequently, these devices with short lifetime fail to meet their commercial needs.
To solve the aforementioned problems, several conventional technical solutions have been proposed as improvements, such as Taiwan Patent No. 570472, Taiwan Patent Publication No. 200603416 (GE), U.S. Pat. No. 6,576,351 B2, U.S. Pat. No. 6,866,901 B2, U.S. Patent Publication No. 2005/0249901 A1, U.S. Patent Publication No. 2006/0226523 A1, U.S. Patent Publication No. 2007/0172971A1, and U.S. Patent Publication No. 2008/0006819 A1.
Taiwan Patent No. 570472 disclosed structural improvements to a package of a flexible optoelectronic device, wherein a high viscoelastic glue and inorganic nano-materials are mixed and dispensed outside the sealant of the non-display area of the optoelectronic device. However, the capability of blocking water vapor and oxygen transmission of the mixed high viscoelastic glue and inorganic nano-materials is not as good as that of metallic layers having the stacking structure of multiple organic layers or multiple inorganic/organic layers. In addition, the bonding reliability of the flexible optoelectronic device is worse.
Taiwan Patent Publication No. 200603416 (GE) disclosed organic electronic packages with hermetically sealed edges and methods of manufacturing such package. According to the disclosed methods, cover plates that are both water vapor and oxygen resistant are implemented to cover the edges of the device with the use of sealants. Although this method is more conducive to water vapor and oxygen resistance than a conventional device, water vapor and oxygen still transmit into the device through the edge sealant, thereby shortening the lifetime of the device.
U.S. Patent Publication No. 2007/0172971 A1 disclosed a method of packaging organic light emitting diodes (OLED), in which the OLED is surrounded by alternately placed sealant and water absorbent materials. However, the water absorbing materials have a limited capability for the absorption of water vapor, and when such a capability is reached, water vapor enters the device region and affects the lifetime of the OLED.